I have this Lua script, which is supposed to create a new class, create an instance and call functions, but there's an error in which I actually call the methods.
Account = { balance = 0, new = function(self,o) o = o or {} setmetatable(o,self) self.__index = self return o end, deposit = function(self,money) self.balance = self.balance + money end, withdraw = function(self,money) self.balance = self.balance - money end } new_account = Account.new() print(new_account.balance) new_account.deposit(23) new_account.deposit(1) print(new_account.balance) It keeps throwing this error:
attempt to call a nil value (field 'deposit') It seems to work like this:
Account = { balance = 0, } function Account:new(o) o = o or {} setmetatable(o,self) self.__index = self return o end function Account:deposit(money) self.balance = self.balance + money end function Account:withdraw(money) self.balance = self.balance - money end function Account:get_balance() return self.balance end acc = Account:new({}) print(acc.balance) acc:deposit(1920) print(acc:get_balance()) I don't seem to get what's wrong. Maybe it's the ':' operator that only works?
1 Answer
Yes, you need to use : to call methods:
new_account = Account:new() print(new_account.balance) new_account:deposit(23) new_account:deposit(1) print(new_account.balance) Account:new() is sugar for Account.new(Account), etc.
